There are many pink ribbon displays and charity walks each year to support the many people diagnosed with breast cancer. Each year leads to more scientific advances and discoveries about how cancer develops and breakthroughs that may lead to more effective treatments. Genes have become an important predictor for how cancer may behave as well as for determining if family members may be at risk to develop cancer too.
Inherited risk factors
Family history and young age of cancer onset have traditionally been considered key factors in predicting the chance that someone may have an inherited risk for cancer. Testing based on personal or family history to determine future risk for cancer diagnosis for oneself or family members is often called “germline genetic testing,” referring to a gene that is passed from parent to child.
In the past two years, cancer behavior has come into focus as a predictor for inherited risk. All women with metastatic breast cancer are now candidates to consider genetic testing — regardless of their age at the time of diagnosis or their family history — because they may have an inherited risk that could be used to tailor and expand their treatment options. If an inherited risk is identified, it may help family members understand their lifetime chances of developing cancer and lead to early detection, risk reduction, or prevention options.
When looking at family history, it is often easiest to spot an inherited risk when several people on one side of the family develop the same kind of cancer. Different types of cancer, however, may also suggest an inherited risk. Common cancer patterns in a family history that should catch attention include breast, ovarian, pancreatic, prostate, and/or colon cancers. A genetic counselor can help discuss your family history, determine the chance of an inherited risk factor, and help you understand testing options, what the test result means for you and your family members, and how you might use the results to guide your medical care.
Tumor testing
Once the cancer has been removed or biopsied (if there is enough tissue), a test may be run on the tumor to determine which genes developed mutations (changes in the instruction of the gene) that may predict how the cancer might behave and potential treatment options the cancer may respond to. This is called a somatic mutation (mutation in the tissue but not inherited) and can be done on parts of the cancer called a tumor block. This type of test gives information about the current tumor, but it does not necessarily predict a gene that was inherited from a parent. Testing on the tumor block may be repeated over time in people with metastatic disease, as the tumor will acquire more changes in the tissue as it grows, and your doctor may wish to look again to determine if additional treatment options are useful.
Inherited mutations
Some mutations in the tumor will suggest the possibility of an inherited mutation. This is why a mutation in a gene associated with a known inherited risk factor (such as BRCA1, BRCA2, PALB2, or ATM) that is identified in the tumor is another reason to see a genetic counselor. Regardless of whether a gene mutation was inherited from a parent or found only in the tumor, your doctor may use that information to determine the kind of chemotherapy that might be useful. Genetic counselors work as a team with your doctor to help you understand and benefit from genetic testing options.
Having the conversation
If you or a family member has metastatic breast cancer, it is important to talk with your doctor or a genetic counselor about genetic testing options. Since metastatic breast cancer is a new reason to consider genetic testing, it may not have been brought up in conversations yet, but it is worthwhile to consider. People often worry what their cancer diagnosis might mean for the cancer risks in their relatives. The genetic test result for someone with metastatic breast cancer may provide helpful information for their family members. Genetic counselors can help you decide if genetic testing is right for you. Learn more at Findageneticcounselor.com.
Joy Larsen Haidle, MS, LGC, is a past-president of the National Society of Genetic Counselors and a genetic counselor at the North Memorial Health Cancer Center in Minneapolis.
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